鄂尔多斯特有种四合木分布区景观格局时空变化

以1977、1990、2000及2005年遥感影像为信息源,利用RS、GIS技术及景观格局分析软件,对鄂尔多斯特有种四合木分布区景观格局的时空变化进行分析。结果表明:在景观水平上,28年来研究区景观格局趋于破碎,景观结构更加复杂并向异质化发展;各生境中,以石嘴山、桃司兔、千里山与乌达种群的景观格局较为破碎,景观构成向多样性与复杂化发展,乌家庙、棋盘井与海南种群中景观受损程度相对较小,景观中有连通度极高的优势斑块类型存在;各景观中,四合木是研究区的基质景观,但其优势地位不断下降,空间分布趋于分散,而工矿及城镇用地、耕地与林地、沙地、其他植被则大幅增长、连片延续发展,在景观中的影响程度逐渐加大。工矿发展和城市化进程以及不合理的土地利用方式引起的土地沙化是四合木减少及其分布区景观格局变化的直接原因。

Spatial-temporal change of landscape pattern in the distribution region of endemic species Tetraena mongolica Maxim. on Ordos Plateau

Using the technology of remote sensing,geographical information system and the analysis software of landscape pattern, the paper analyzed four sensing images of Tetraena mongolica distribution region in different periods (1977, 1990, 2000, 2005) to study the dynamic changes of temporal and spatial landscape patterns based on the images interpretation and landscape classification and cartography and the calculation of landscape index, The results show: (1) On landscape scale, patch number, landshape index, Shannon's diversity index and Shannon's evenness index were increased, while mean patch size and dominance index were decreased year after year. It is indicated that the landscape pattern tended to be fragmented, landscape components tended to be complicated in the distribution region of T. mongolica. (2) In the different habitats of Tetraena mongolica the landscape patterns in Shizuishan, Taositu, Qianlishan and Wuda populations were fragmented. The landscape structure tended to be diversified and complicated. While the landscape patterns in Wujiamiao, Qipanjing and Hainan populations were relatively integrated because of less severe human driving force. And there were preponderant patches connected each other in the landscape. (3) Of all of the landscape types, T. mongolica was the maximal landscape component and basic landscape type in the research region, but its dominant status was reduced in the 28-year period of and its distribution tended to be dispersed and fragmented. Besides the land for industrial, urban construction and farming purposes as well as desertified land and other vegetations were largely increased and tended to be connected. Their functions in the landscape were increasing gradually. (4) It is indicated that the industrial development and rapid urbanization and land desertification caused by irrational land use were direct reasons for the T.mongolica population area reduction and landscape pattern change of the research region.